1. Technical Field
This invention relates to a traction-type elevator and particularly to such an elevator in which the cage is moved vertically with ropes via a hoist.
2. Description of the Prior Art
FIGS. 4-6 illustrate conventional traction-type elevators. In FIGS. 4 and 5, a cage (101) is arranged in a vertically movable manner in a channel (102). A pair of sheaves (104) and (105) for the cage is arranged through a cage frame (103) on the upper portion of the cage (101). Multiple ropes (106), (107), and (108) are engaged on cage sheaves (104) and (105). These ropes (106), (107), and (108) are also engaged on a driving sheave (110) of a hoist (109). Also, one end of ropes (106), (107), and (108) is fixed on an overhead beam (111), while the other end is fixed on a counterweight (112). Of course, the hoist (109) or motor is electronically connected to a controller, both connected to suitable electrical power sources, all as is well-known.
As is well known, the diameter of the sheaves (104) and (105) is determined by the size of ropes (106), (107), and (108). Consequently, when sheaves (104) and (105) are relatively larger, it becomes impossible to arrange the sheaves (104) and (105) along the steering the frame (103). Instead, they must be arranged at an angle to frame (103) (that is, diagonal to the cage (101)). Then, multiple ropes (106), (107), (108) are hung on obliquely arranged sheaves (104), (105), and they are hung on the driving sheave (110) above the sheave (104).
For the conventional traction-type elevator with cage sheaves (104) and (105) arranged in the diagonal direction of the cage (101), as shown in FIG. 6, for ropes (106), (107), (108) hung from cage sheave (104) to driving sheave (110), the overall shape of the ropes is slightly twisted. More specifically, as cage (101) moves to the upper floors, the amount of twisting of the overall of said ropes (106), (107), (108) under the action of driving sheave (110), said ropes (106), (107), (108) twist. Consequently, vibration and noise take place (in particular, when cage (101) moves vertically at a high speed.) This is a disadvantage.
It is a principal object of the present invention to solve the aforementioned problems of the conventional methods by providing a traction-type elevator characterized by the fact that the ropes can be hung from the cage sheaves to the driving sheave without twisting; thus, no vibration or noise is generated from the ropes under traction.
According to the present invention, a traction-type elevator includes a driving sheave arranged in the upper portion of the channel, a cage sheave arranged at an angle on the upper side of the cage and opposite to said driving sheave, and multiple ropes hung on the periphery of said cage and the periphery of said driving sheave; in this traction-type elevator, the periphery of said cage sheave is arranged nearly parallel to the periphery of the driving sheave, and said cage sheave is divided into multiple sheave pieces corresponding to said ropes.
Because the periphery of the overall sheave pieces is almost parallel to the periphery of the driving sheave, there is no overall twisting of the multiple ropes hung from said sheave pieces to the driving sheave, and the ropes can become taut without twisting. That is, during the movement of the cage to an upper floor, the ropes have no overall twist. Consequently, even when the multiple ropes are pulled by the driving sheave, and the cage moves vertically at a high speed, the ropes are still free of overall twisting; hence, no vibration or noise is generated.
Further and still other objects of the present invention will become more readily apparent when the following detailed description is taken in conjunction with the accompanying drawing, in which: